Public Class Form1 Private Sub Button1_Click(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles Button1.Click Dim n,t,s,m As Double m = Val(TextBox1.Text) s = 2.0# For n = 1 To m t = (2 * n) ^ 2 / ((2 * n - 1) * (2 * n + 1)) s *= t Next Label2.Text = "π的近似值为" & s End Sub Private Sub Form1_Load(ByVal sender As System.Object,ByVal e As System.EventArgs) Handles MyBase.Load End Sub End Class